1. Field of the Invention
The present invention relates to electronic devices and, more particularly, to portable electronic devices that can couple to peripheral buses.
2. Description of the Related Art
Portable electronic devices, such as Portable Digital Assistants and media players, are often battery powered. These electronic devices sometimes also have peripheral bus ports that are able to support peripheral buses, such as Universal Serial Bus (USB) or FIREWIRE (IEEE 1394) bus ports. Peripheral buses are used to provide data communications with electronic devices as well as to provide limited amounts of power to the electronic devices.
Recently, the iPod®, a media player developed by Apple Computer, Inc. of Cupertino, Calif., has been able to charge its battery through power provided to its FIREWIRE bus port. Although charging batteries or otherwise powering an electronic device via a peripheral bus is convenient, peripheral buses are not designed to carry large amounts of power. In the case of a USB bus, the available power is limited to about 0.5 Watts but can be increased to about 2.5 Watts through a negotiation process. Unfortunately, not only is the negotiation process cumbersome, but the amount of power (even when increased through negotiation) is still often inadequate for many electronic devices.
Thus, there is a need to facilitate greater power delivery to electronic devices via peripheral buses.